1. Field of the Invention
The present invention relates to a lighting device for both normal and emergent use.
2. Description of the Related Art
Electricity is important for providing illumination in public and household areas. In addition to normal lighting devices, emergent lighting devices are also required to provide illumination when power supply is not available due to, e.g., planned or accidental interruption of service. An emergent lighting device is an independent illuminating device that is charged by a power source to store electricity in a battery unit. The emergent lighting device will be automatically turned on when normal power supply is not available.
FIG. 1 of the drawings illustrates a lighting device 1 that includes an emergent light and a normal ordinary light that share a common light base 13 and a light hood 14. An emergent lighting element 12 is connected to an uninterrupted power supply 15 such that the lighting device 1 may be used for both normal and emergent illumination. However, the lighting element 11 for normal illumination and the emergent lighting element 12 are separate elements although they share a common light base 13. The lighting device 1 still has to include at least two sets of lighting elements for normal and emergent illumination, respectively, which is troublesome and costly.
It is the primary object of the present invention to provide an improved lighting device for both normal and emergent use.
A lighting device in accordance with the present invention comprises a lighting unit, a stabilizer electrically connected to the lighting unit, and a circuit board. The circuit board comprises a detecting circuit having a first end electrically connected to a power source; a converter including a first end electrically connected to a second end of the detecting circuit, the converter being electrically connected to a battery unit; a switch for selectively conducting the lighting unit with one of the power source and the converter; an isolating circuit electrically mounted between the battery unit and the power source; a rectifier mounted in front of the battery unit and electrically connected to the power source, the battery unit being electrically connected to the rectifier so as to be charged during a normal illumination state; and a relay electrically connected to the switch for selectively controlling conduction with one of the power source and the converter.
When at the normal illumination state, electric current from the power source passes through the stabilizer to turn on the lighting unit, and the power source charges the battery unit.
When at an emergent illumination state, upon detection of interruption service by the detecting circuit, the relay activates the switch of the lighting unit to be non-conductive with the power source and be conductive with the converter, and the converter is empowered by the battery unit.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.